The present invention relates to an oil regulating pump and more particularly to the pump which may be utilized to supply oil to an engine and regulate the supply oil flow via a motor.
In a conventional oil regulating pump of this type, as illustrated in FIG. 12, a primary plunger 8 which is connected with a driving shaft 5 is slidably disposed within a pump casing 3 and is urged by a spring 9.
Since the driving shaft 5 is driven and rotated by an engine rotation force and the primary plunger 8 is rotated in accordance with rotation of the driving shaft 5, an oil suction route and an oil discharge route between the primary plunger 8 and the pump casing 3 are opened and closed, thereby supplying the oil to the engine.
Moreover, a volume of a pump chamber (not illustrated) which is formed between the primary plunger 8 and a secondary plunger 10 inserted into a hole provided in the primary plunger 8 is regulated by a cam shaft 48, because an eccentricity rate of an eccentric cam 47 can be changed by the rotation of the cam shaft 48, also because a position where the controlling cam 5A and the eccentric cam 47 abut is set by the eccentricity rate of the eccentric cam 47. That is, an oil discharge flow rate of said oil regulating pump is controlled by a rotation number and a stroke regulation of the driving shaft 5, and the pump rotation number is adapted to correspond to the engine rotation number. Because the rotation of the driving shaft 5 is reduced while the engine rotation is transmitted to the driving shaft 5 via a worm gear 6 at this time, the pump rotation number shows a value multiplying the engine rotation number by this reduction rate.
Meanwhile, two cam pins 7 are provided in positions opposite to a radial direction of a circumferential end of the driving shaft 5 and one controlling cam 5A is provided at a center in the end of the driving shaft 5, and the eccentric cam 47 is disposed in the cam shaft 48 (hereinafter referred to as a controlling shaft 48) wherein the eccentric cam 47 can be abutted on the controlling cam 5A. Therefore the position where the eccentric cam 47 abuts on the controlling cam 5A is changed by rotation of said controlling shaft 48, that is, due to eccentricity rate of the eccentric cam 47, the stroke of the primary plunger 8 can be changed, thereby controlling the oil flow.
However, in case of the above structure, the eccentric cam 47 requires high machining accuracy and also is difficult to machine because a shape of the eccentric cam 47 and a difference in angle between the eccentric cam 47 and the controlling shaft 48 causes a difference in contact between the controlling cam 5A and the eccentric cam 47, which results in a difference in stroke or a difference in flow rate. Also, regulation of the oil flow due to engine load is impossible and only the engine rotation number is controlled during a travelling time, because the stroke is manually regulated.